I created a portfolio of 5 one sided forms and one 2 sided form. Is there a way to toggle my printer (Brother MFC8960DW) into duplex mode when printing the 2 sided form and back to one sided mode for printing the rest of the portfolio?

Have you tried setting the Document Properties for your double-sided form file only? File > Properties > Advanced tab and then set the Duplexmode. This will set this propertyfor just this specific PDF.

Did this resolve the issue? I am having the same problem. I am using XI Pro. If this is the fix do I need to make those changes in the individual double sided documents before I add them to the portfolio or after? I cant find the settings after I have added the files to the portfolio.

Right now everything is printing duplex and I can not figure out why because it appears it is set to simplex.